Maybe something like a publicly traded company, Citizens can vote directly on individual bills, or choose a proxy to vote on their behalf (and change that choice at any point that desire).

It wouldn't actually change anything, because your single direct vote wouldn't have any outcome at all. It would by negligible compared to all the votes from the proxies, because they represent millions and you just one. It would result in the same outcome, talking to the proxy gets your point better across than voting yourself.